1 / 17

Unit 0: Observation, Measurement and Calculations

Unit 0: Observation, Measurement and Calculations. Cartoon courtesy of NearingZero.net. Precision and Accuracy. Accuracy refers to the agreement of a particular value with the true value. Precision refers to the degree of agreement among several measurements made in the same manner.

illiana-kaufman
Download Presentation

Unit 0: Observation, Measurement and Calculations

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Unit 0:Observation,Measurementand Calculations Cartoon courtesy of NearingZero.net

  2. Precision and Accuracy • Accuracyrefers to the agreement of a particular value with the truevalue. Precisionrefers to the degree of agreement among several measurements made in the same manner. Precise but not accurate Precise AND accurate Neither accurate nor precise

  3. The Fundamental SI Units(le Système International, SI)

  4. Uncertainty in Measurement • A digit that must be estimated is called uncertain. A measurement always has some degree of uncertainty.

  5. Why Is there Uncertainty? • Measurements are performed with instruments • No instrument can read to an infinite number of decimal places Which of these balances has the greatest uncertainty in measurement?

  6. Rules for Counting Significant Figures - Details • Nonzero integersalways count as significant figures. 3456has 4sig figs.

  7. Rules for Counting Significant Figures - Details • Zeros -Leading zeros do not count as significant figures. • 0.0486 has 3 sig figs.

  8. Rules for Counting Significant Figures - Details • Zeros -Captive zeros always count as significant figures. • 16.07 has 4 sig figs.

  9. Rules for Counting Significant Figures - Details • Zeros Trailing zerosare significant only if the number contains a decimal point. 9.300 has 4 sig figs.

  10. Rules for Counting Significant Figures - Details • Exact numbers AND Counted #shave an infinite number of significant figures. 1 inch = 2.54cm, exactly 240 chocolate kisses

  11. Sig Fig Practice #1 How many significant figures in each of the following? 1.0070 m  5 sig figs 17.10 kg  4 sig figs 100,890 L  5 sig figs 3.29 x 103 s  3 sig figs 0.0054 cm  2 sig figs 3,200,000  2 sig figs

  12. Rules for Significant Figures in Mathematical Operations • Multiplication and Division:# sig figs in the result equals the number in the least precise measurement used in the calculation. 6.38 x 2.0 = 12.76 13 (2 sig figs)

  13. Sig Fig Practice #2 Calculation Calculator says: Answer 22.68 m2 3.24 m x 7.0 m 23 m2 100.0 g ÷ 23.7 cm3 4.22 g/cm3 4.219409283 g/cm3 0.02 cm x 2.371 cm 0.05 cm2 0.04742 cm2 710 m ÷ 3.0 s 236.6666667 m/s 240 m/s 5870 lb·ft 1818.2 lb x 3.23 ft 5872.786 lb·ft 2.9561 g/mL 2.96 g/mL 1.030 g ÷ 2.87 mL

  14. Rules for Significant Figures in Mathematical Operations • Addition and Subtraction: The number of decimal places in the result equals the number of decimal places in the least precise measurement. 6.8 + 11.934 = 18.734  18.7 (3 sig figs)

  15. Sig Fig Practice #3 Calculation Calculator says: Answer 10.24 m 3.24 m + 7.0 m 10.2 m 100.0 g - 23.73 g 76.3 g 76.27 g 0.02 cm + 2.371 cm 2.39 cm 2.391 cm 713.1 L - 3.872 L 709.228 L 709.2 L 1821.6 lb 1818.2 lb + 3.37 lb 1821.57 lb 0.160 mL 0.16 mL 2.030 mL - 1.870 mL

More Related